Porous SiC ceramics are a type of materials made of silicon carbide (SiC) which have an infinite number of micro pores. They have excellent thermal and electrical insulation properties as well as good heat resistance, and therefore, are expected to be used for functional structures in nuclear energy systems, sustainable-energy systems and other similar systems.
Conventional porous SiC ceramics are produced by forming a material into a certain shape and sintering it by an appropriate sintering method, such as the pressureless sintering, reaction sintering or macromolecule sintering. However, porous SiC ceramics produced by these conventional methods have low strengths due to the weak bonding force between SiC molecules. This means that the product easily cracks by a shock or the like, so that it cannot be used as a structural material.
Given this problem, attempts have been made to provide porous SiC ceramics with an increased strength.
For example, Non-Patent Document 1 discloses a porous SiC ceramic produced by sintering a mixture of SiC powder and carbon powder under high pressure and high temperature, and subjecting the sintered product to a decarburization process. In the porous SiC ceramic according to this document, the portions other than the pores are sintered with a strong bonding force, making the product remarkably higher in strength than conventional ones.